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Outlook 2010 cannot open Exchange 2010 Public Folder.

Question

I am in the process of transitioning from Exchange 2003 to Exchange 2010 SP1 Update Rollup 4. I have 5 users on the new mail server and the rest are on the old mail server. All users are using Outlook 2010. Outlook clients cannot open the public folders.
They receive a message:Cannot expand the folder. Microsoft Exchange is not available. Either there are network problems
or the Exchange computer is down for maintenance. I have read some other posts and users were able to reboot their servers to correct the problem. I have rebooted a number of times w/o successfully resolving my issue.

Since this is SP1 EncryptionRequired:False on the RPC but I don't know that it matters.

I have run AddReplicaToPFRecursive script and the new PF DB from Exchange 2010 is added
to the replication tab of the PFs on Exchange 2003. Again, OWA users can see the PFs just fine. I have already added the EXchange 2010 PF DB to the users mailbox database.

Answers

The Outlook 2010 client was configured to connect using Outlook Anywhere. My client workstation was not joined to the domain and when Outlook 2010 would open I was not prompted for credentials. I could see in the Outlook Connection Status tool that it would
attempt to connect to the Public Folders and then would drop the connection attempt. The security log on the mailbox server showed a failed audit for a logon.

I change the Outlook profile setting so that it would always ask me for my credentials when connecting. I restarted Outlook 2010 and entered my credentials, checked the Exchange Connection Status window and saw that the Public Folders was now connected!

I'm not quite sure why I wasn't require to enter my credentials every time Outlook opened but I wasn't. This caused and issue connecting and authenticating to the Public Folder DB on the mail server.

I also setup a workstation that was joined to the domain with Outlook 2010 installed. I configured my profile and was not asked for credentials (because I was already logged in to a computer on the domain as the Outlook users that I was connecting as. Public
Folders appear w/o any issue.

Amazing how I spent hours troubleshooting myself and also 7 hours on the phone with Microsoft and no one ever thought to look at the Outlook settings. I admit that I had two competent Exchange techs on the line and not an Outlook tech. Once the tech and
I narrowed it down to an Outlook issue I started poking around myself while on hold and hit a home run.

The public folders are definitely there. There are some ~5700 items. Don't chide me yet, I'm new to the company and they used public folders like a major repository.

Thru some testing I have determined that the issues lies with Outlook 2010. I have setup the same mailboxes on an Outlook 2003 client and I am able to view the public folders. Still cannot view public folders with Outlook 2010.

I have recreated the PF DB so it was empty and created a new folder. OWA & Outlook 2003 sees the new folder but not Outlook 2010. PFs started to replicate automatically from Exchange 2003 to Exchange 2010... Outlook 2003 & OWA sees the newly replicated
content but not Outlook 2010.

The Outlook 2010 client was configured to connect using Outlook Anywhere. My client workstation was not joined to the domain and when Outlook 2010 would open I was not prompted for credentials. I could see in the Outlook Connection Status tool that it would
attempt to connect to the Public Folders and then would drop the connection attempt. The security log on the mailbox server showed a failed audit for a logon.

I change the Outlook profile setting so that it would always ask me for my credentials when connecting. I restarted Outlook 2010 and entered my credentials, checked the Exchange Connection Status window and saw that the Public Folders was now connected!

I'm not quite sure why I wasn't require to enter my credentials every time Outlook opened but I wasn't. This caused and issue connecting and authenticating to the Public Folder DB on the mail server.

I also setup a workstation that was joined to the domain with Outlook 2010 installed. I configured my profile and was not asked for credentials (because I was already logged in to a computer on the domain as the Outlook users that I was connecting as. Public
Folders appear w/o any issue.

Amazing how I spent hours troubleshooting myself and also 7 hours on the phone with Microsoft and no one ever thought to look at the Outlook settings. I admit that I had two competent Exchange techs on the line and not an Outlook tech. Once the tech and
I narrowed it down to an Outlook issue I started poking around myself while on hold and hit a home run.

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